Thin film forming device for forming silicon thin film having crystallinity

Abstract

An insulating member is interposed between a film formation chamber container and a plasma chamber container. Both containers are adjacent to and communicated with each other. In the film formation chamber container, a base material holder is provided for holding the base material. Raw material gas is introduced into the plasma chamber container and ionized by high frequency electric discharge, to generate plasma. A high frequency electrode and a high frequency electric power source are provided as a plasma generating unit. There is provided a porous electrode 30 , the electric potential of which is the same as that of the plasma chamber container 24, between both chambers 22, 24 to partition both chambers. A pulse electric powder source for impressing bipolar pulse voltage, in which a positive polarity portion and a negative polarity portion are alternately repeated, is provided between the base material holder and both of the plasma chamber container and the porous electrode 30, the electric potential of which is the same as that of the plasma chamber container 24.

What is claimed is:  
     
       1. A thin film forming device for forming a silicon thin film having crystallinity comprising: 
       a film formation chamber container from which gas is exhausted to vacuum;  
       an insulating member;  
       a plasma chamber container which is adjacent to the film formation chamber container via the insulating member so that the plasma chamber container is insulated from the film formation chamber container, wherein at least one of raw material gas and a mixture gas containing raw material gas and inert gas is being introduced into the plasma chamber container;  
       plasma generation means for generating plasma in the plasma chamber container by ionizing the introduced raw material gas;  
       a porous electrode having small pores arranged to partition the plasma chamber container and the film formation chamber container from each other, the electric potential of the porous electrode being the same as that of the plasma chamber container;  
       a base material holder for holding a base material so that the base material can be directed to the porous electrode, the base material holder being arranged in the film formation chamber container to be opposed to the porous electrode; and  
       a pulse power source for impressing a bipolar pulse voltage, in which a positive polarity portion and a negative polarity portion are alternately repeated, between the base material holder and both the plasma chamber container and the porous electrode.  
     
     
       2. The thin film forming device according to claim  1 , wherein the plasma generation means comprises: 
       a high frequency electrode arranged in the plasma chamber container, the high frequency electrode being electrically insulated from the plasma chamber container; and  
       a high frequency power source for supplying high frequency electric power between the high frequency electrode and the plasma chamber container to generate a high frequency electric discharge between them and ionize the raw material gas.  
     
     
       3. The thin film forming device according to claim  1 , wherein the plasma generation means comprises: 
       a microwave power source for introducing microwaves into the plasma chamber container to generate a microwave electric discharge in the plasma chamber container and ionize the raw material gas; and  
       a microwave introducing means for introducing the microwaves generated by the microwave electric power source into the plasma chamber container.  
     
     
       4. The thin forming device according to claim  1 , wherein the frequency of bipolar pulse voltage is in the range of 10 Hz to 1000 Hz. 
     
     
       5. The thin film forming device according to claim  1 , wherein the voltage of the positive polarity portion of the bipolar pulse voltage is in the range of 100 V to 1000 V. 
     
     
       6. The thin film forming device according to claim  1 , wherein the voltage of the negative polarity portion of the bipolar pulse voltage is in the range of 5 V to 100 V. 
     
     
       7. The thin film forming device according to claim  1 , further comprising heating means for heating the base member at 400° C. or less. 
     
     
       8. The thin film forming device according to claim  1 , wherein a duty ratio of the bipolar pulse voltage is not lower than 50%. 
     
     
       9. A thin film forming device for forming a thin crystalline film comprising: 
       a film formation chamber container;  
       an insulating member;  
       a plasma chamber container that is adjacent to the film formation chamber container via the insulating member such that the plasma chamber container is insulated from the film formation chamber container;  
       plasma generation means for generating plasma in the plasma chamber container by ionizing gas that is introduced into the plasma chamber container;  
       a base material holder located in the film formation chamber for holding a base material;  
       a porous electrode that includes small pores, wherein the electric potential of the porous electrode is the same as that of the plasma chamber container and wherein the porous electrode is arranged opposite to the base material holder, and partitions the plasma chamber container and the film formation chamber container from each other to prevent the base material in the film formation chamber container from being directly exposed to the plasma; and  
       a pulse power source for impressing a bipolar pulse voltage, in which a positive polarity portion and a negative polarity portion are alternately repeated between the base material holder and both the plasma chamber container and the porous electrode, wherein the pulse power source assists in forming a thin crystalline film without heating the base material to a high temperature.  
     
     
       10. The thin film forming device according to claim  9 , wherein the plasma generation means comprises: 
       a high frequency electrode arranged in the plasma chamber container, the high frequency electrode being electrically insulated from the plasma chamber container; and  
       a high frequency power source for supplying high frequency electric power between the high frequency electrode and the plasma chamber container to generate a high frequency electric discharge between them and ionize the introduced gas.  
     
     
       11. The thin film forming device according to claim  9 , wherein the plasma generation means comprises: 
       a microwave power source for introducing microwaves into the plasma chamber container to generate a microwave electric discharge in the plasma chamber container and ionize the introduced gas; and  
       a microwave introducing means for introducing the microwaves generated by the microwave electric power source into the plasma chamber container.  
     
     
       12. The thin film forming device according to claim  9 , wherein the frequency of bipolar pulse voltage is in the range of 10 Hz to 1000 Hz. 
     
     
       13. The thin film forming device according to claim  9 , wherein the voltage of the positive polarity portion of the bipolar pulse voltage is in the range of 100 V to 1000 V. 
     
     
       14. The thin film forming device according to claim  9 , wherein the voltage of the negative polarity portion of the bipolar pulse voltage is in the range of 5 V to 100 V. 
     
     
       15. The thin film forming device according to claim  9 , further comprising heating means for heating the base member at 400° C. or less. 
     
     
       16. The thin film forming device according to claim  9 , wherein a duty ratio of the bipolar pulse voltage is not lower than 50%.